Question 1

Candle jars are usually used to

Accepted Answer

A)  prevent candles from melting. 
B)  provide an atmosphere with CO2. 
C)  stimulate the growth of obligate anaerobes. 
D)  prevent the growth of obligate aerobes. 
E)  enhance the growth of microaerophiles. 
A)  prevent candles from melting. 
B)  provide an atmosphere with CO2. 
C)  stimulate the growth of obligate anaerobes. 
D)  prevent the growth of obligate aerobes. 
E)  enhance the growth of microaerophiles.

Question 2

In some labs, samples containing suspected L. pneumophila are cultured on traditional BCYE medium as well as BCYE medium lacking L-cysteine. How would L. pneumohila be identified in this situation?

Accepted Answer

A)  Compare the two plates. Colonies that grow on traditional BYCE medium but not on BYCE medium lacking cysteine are likely L. pneumophila. 
B)  Compare the two plates. Colonies that grow on BYCE medium lacking cysteine but not on traditional BYCE medium are likely L. pneumophila. 
C)  Compare the two plates. Colonies that grow on both traditional BYCE medium and on BYCE medium lacking cysteine are likely L. pneumophila. 
D)  Compare the two plates. Colonies that do not grow on traditional BYCE medium or on BYCE medium lacking cysteine, but do grow on nutrient agar are likely L. pneumophila. 
E)  Compare the two plates. Colonies that grow on traditional BYCE medium and are blue, yellow or cyan in color are likely L. pneumophila. 
A)  Compare the two plates. Colonies that grow on traditional BYCE medium but not on BYCE medium lacking cysteine are likely L. pneumophila. 
B)  Compare the two plates. Colonies that grow on BYCE medium lacking cysteine but not on traditional BYCE medium are likely L. pneumophila. 
C)  Compare the two plates. Colonies that grow on both traditional BYCE medium and on BYCE medium lacking cysteine are likely L. pneumophila. 
D)  Compare the two plates. Colonies that do not grow on traditional BYCE medium or on BYCE medium lacking cysteine, but do grow on nutrient agar are likely L. pneumophila. 
E)  Compare the two plates. Colonies that grow on traditional BYCE medium and are blue, yellow or cyan in color are likely L. pneumophila.

Question 3

During which phase of growth are bacteria most susceptible to antibiotics?

Accepted Answer

A)  Lag 
B)  Stationary 
C)  Exponential (log) 
D)  Decline 
E)  Infection 
A)  Lag 
B)  Stationary 
C)  Exponential (log) 
D)  Decline 
E)  Infection

Question 4

Eosin methylene blue agar (EMB) is a selective and differential medium. The dyes in the medium inhibit most Gram-positive organisms. Gram-negative organisms such as the coliforms grow on this medium. Coliforms that are fecal in origin produce colonies with a metallic green color on EMB, while those that are non-fecal produce colorless colonies. You plate a urine sample onto an EMB plate and incubate it. Metallic green colonies develop. From this, you can conclude that

Accepted Answer

A)  the sample contains bacteria that are Gram-negative AND are non-fecal in origin. 
B)  the sample contains bacteria that are Gram-negative AND are fecal in origin. 
C)  the sample contains bacteria that are Gram-positive AND are fecal in origin. 
D)  the bacteria in the colonies are Gram-positive AND are rod-shaped. 
E)  normal microbiota in the bladder is fecal in origin AND is aerobic. 
A)  the sample contains bacteria that are Gram-negative AND are non-fecal in origin. 
B)  the sample contains bacteria that are Gram-negative AND are fecal in origin. 
C)  the sample contains bacteria that are Gram-positive AND are fecal in origin. 
D)  the bacteria in the colonies are Gram-positive AND are rod-shaped. 
E)  normal microbiota in the bladder is fecal in origin AND is aerobic.

Question 5

In a rapidly multiplying bacterial population, cell numbers increase

Accepted Answer

A)  arithmetically. 
B)  logarithmically. 
C)  linearly. 
D)  indirectly. 
E)  additionally. 
A)  arithmetically. 
B)  logarithmically. 
C)  linearly. 
D)  indirectly. 
E)  additionally.

Question 6

Organisms that use organic molecules as their source of carbon are called

Accepted Answer

A)  chemotrophs. 
B)  heterotrophs. 
C)  organoheterotrophs. 
D)  autotrophs. 
E)  organoautotrophs. 
A)  chemotrophs. 
B)  heterotrophs. 
C)  organoheterotrophs. 
D)  autotrophs. 
E)  organoautotrophs.

Question 7

A halophilic, aerobic mesophile has a generation time of 20 minutes. You place 1 × 104 of these organisms on an appropriate solid medium, and incubate the plate for 100 minutes. Select the FALSE statement.

Accepted Answer

A)  The growth medium contains NaCl. 
B)  The organism will grow at 40oC. 
C)  After incubation, a colony on the plate contains 3.2 × 105 cells. 
D)  After incubation, a colony on the plate contains 5 × 104 cells. 
E)  The organism produces superoxide dismutase and catalase. 
A)  The growth medium contains NaCl. 
B)  The organism will grow at 40oC. 
C)  After incubation, a colony on the plate contains 3.2 × 105 cells. 
D)  After incubation, a colony on the plate contains 5 × 104 cells. 
E)  The organism produces superoxide dismutase and catalase.

Question 8

A single bacterial cell may multiply to form a visible colony.

Accepted Answer

A) True 
 B)False

Question 9

You are determining the number of colony forming units (CFUs) for Susan, who has a urinary tract infection (UTI). You added 1 mL of Susan's urine sample to 99 mL of diluent, and spread 0.1 mL of that dilution on a culture medium. After appropriate incubation, you count 143 colonies on the plate. What was the concentration of bacteria in the original urine sample?

Accepted Answer

A)  1.43 cells/ mL 
B)  1.43 × 102 cells/ mL 
C)  1.43 × 103 cells/ mL 
D)  1.43 × 105 cells/ mL 
E)  Cannot be determined 
A)  1.43 cells/ mL 
B)  1.43 × 102 cells/ mL 
C)  1.43 × 103 cells/ mL 
D)  1.43 × 105 cells/ mL 
E)  Cannot be determined

Question 10

The optimal temperature for most human pathogens might be expected to range from

Accepted Answer

A)  20-45°C. 
B)  35-40°C. 
C)  15-25°C. 
D)  93-98.6°C. 
E)  35-40°F 
A)  20-45°C. 
B)  35-40°C. 
C)  15-25°C. 
D)  93-98.6°C. 
E)  35-40°F

Question 11

If you are asked to make 200 mL of Thayer-Martin agar, who much sheep's blood would you add to the medium? Recall that this complex medium contains 5% sheep blood.

Accepted Answer

A)  10% 
B)  5 mL 
C)  10 mL 
D)  Random quantities 
E)  10,000 RBCs 
A)  10% 
B)  5 mL 
C)  10 mL 
D)  Random quantities 
E)  10,000 RBCs

Question 12

High concentrations of salt and sugar in foods

Accepted Answer

A)  are useful in preserving the food AND tend to force water into a cell, causing plasmolysis. 
B)  have no effect on water availability AND are useful in preserving the food. 
C)  are useful in preserving the food AND tend to draw water out of a cell. 
D)  are useful in preserving the food AND force bacteria to divide 
E)  tend to force water into a cell, causing plasmolysis AND force bacteria to divide 
A)  are useful in preserving the food AND tend to force water into a cell, causing plasmolysis. 
B)  have no effect on water availability AND are useful in preserving the food. 
C)  are useful in preserving the food AND tend to draw water out of a cell. 
D)  are useful in preserving the food AND force bacteria to divide 
E)  tend to force water into a cell, causing plasmolysis AND force bacteria to divide

Question 13

The lab technicians culture the sample on Thayer-Martin agar. This complex medium contains 5% sheep blood and a combination of antibiotics. This medium is

Accepted Answer

A)  differential. 
B)  selective AND differential. 
C)  selective. 
D)  aerobic. 
E)  chemically defined. 
A)  differential. 
B)  selective AND differential. 
C)  selective. 
D)  aerobic. 
E)  chemically defined.

Question 14

L. pneumophila is widespread and is found in various water sources, including hot tubs, water cooling towers, swimming pools, grocery store misters, and shower water. Select the FALSE statement regarding the organism, given this information.

Accepted Answer

A)  It survives in the presence of chlorine. 
B)  It is a mesophile. 
C)  It is an obligate anaerobe. 
D)  It can survive in water pipes. 
E)  It is a mesophile AND it can survive the presence of chlorine. 
A)  It survives in the presence of chlorine. 
B)  It is a mesophile. 
C)  It is an obligate anaerobe. 
D)  It can survive in water pipes. 
E)  It is a mesophile AND it can survive the presence of chlorine.

Question 15

The colonies of interest in this case are the blue-green presumptive Shigella colonies. However, growth on hektoen enteric agar is not sufficient for definitive identification. Further tests are needed. First, the lab technicians need to prepare larger numbers of Shigella from your patient's stool sample, and then they need to ensure that they are culturing a single species. The methods used to do this are ________, followed by ________.

Accepted Answer

A)  streak plating; pour plates 
B)  enrichment culture; Gram staining 
C)  Gram staining; enrichment culture 
D)  Gram staining; capsule staining 
E)  enrichment culture; streak plating 
A)  streak plating; pour plates 
B)  enrichment culture; Gram staining 
C)  Gram staining; enrichment culture 
D)  Gram staining; capsule staining 
E)  enrichment culture; streak plating

Question 16

One would expect most strict anaerobic organisms to have superoxide dismutase.

Accepted Answer

A) True 
 B)False

Question 17

The enzymes that deal with toxic oxygen-containing molecules is/are

Accepted Answer

A)  glycolase AND superoxide dismutase. 
B)  superoxide dismutase AND cytochrome oxidase. 
C)  superoxide dismutase AND catalase. 
D)  catalase AND cytochrome oxidase. 
E)  cytochrome oxidase AND glycolase. 
A)  glycolase AND superoxide dismutase. 
B)  superoxide dismutase AND cytochrome oxidase. 
C)  superoxide dismutase AND catalase. 
D)  catalase AND cytochrome oxidase. 
E)  cytochrome oxidase AND glycolase.

Question 18

Chemoheterotrophs

Accepted Answer

A)  use sunlight as an energy source. 
B)  use preformed organic molecules as a carbon source. 
C)  use preformed organic molecules as an energy source. 
D)  use inorganic chemicals as an energy source. 
E)  use preformed organic molecules as a carbon source AND as an energy source. 
A)  use sunlight as an energy source. 
B)  use preformed organic molecules as a carbon source. 
C)  use preformed organic molecules as an energy source. 
D)  use inorganic chemicals as an energy source. 
E)  use preformed organic molecules as a carbon source AND as an energy source.

Question 19

In nature, bacteria

Accepted Answer

A)  seldom grow in close association with many other kinds of organisms. 
B)  always go through a very short exponential phase. 
C)  occasionally synthesize structures such as slime layers. 
D)  may adhere to surfaces by means of pili and slime layers. 
E)  All of the answer choices are correct. 
A)  seldom grow in close association with many other kinds of organisms. 
B)  always go through a very short exponential phase. 
C)  occasionally synthesize structures such as slime layers. 
D)  may adhere to surfaces by means of pili and slime layers. 
E)  All of the answer choices are correct.

Question 20

What would true about an organism called Bacillus fastidiosus?

Accepted Answer

A)  It might be expected to be very flexible in its growth requirements. 
B)  It might be expected to be very strict in its growth requirements. 
C)  It could probably be grown on a minimal medium. 
D)  It might be expected to have a spherical shape. 
E)  It might be expected to depend on sunlight for energy. 
A)  It might be expected to be very flexible in its growth requirements. 
B)  It might be expected to be very strict in its growth requirements. 
C)  It could probably be grown on a minimal medium. 
D)  It might be expected to have a spherical shape. 
E)  It might be expected to depend on sunlight for energy.

Exam 4: Dynamics of Microbial Growth

Candle jars are usually used to

In some labs, samples containing suspected L. pneumophila are cultured on traditional BCYE medium as well as BCYE medium lacking L-cysteine. How would L. pneumohila be identified in this situation?

During which phase of growth are bacteria most susceptible to antibiotics?

In a rapidly multiplying bacterial population, cell numbers increase

Organisms that use organic molecules as their source of carbon are called

A halophilic, aerobic mesophile has a generation time of 20 minutes. You place 1 × 104 of these organisms on an appropriate solid medium, and incubate the plate for 100 minutes. Select the FALSE statement.

A single bacterial cell may multiply to form a visible colony.

The optimal temperature for most human pathogens might be expected to range from

If you are asked to make 200 mL of Thayer-Martin agar, who much sheep's blood would you add to the medium? Recall that this complex medium contains 5% sheep blood.

High concentrations of salt and sugar in foods

The lab technicians culture the sample on Thayer-Martin agar. This complex medium contains 5% sheep blood and a combination of antibiotics. This medium is

L. pneumophila is widespread and is found in various water sources, including hot tubs, water cooling towers, swimming pools, grocery store misters, and shower water. Select the FALSE statement regarding the organism, given this information.

One would expect most strict anaerobic organisms to have superoxide dismutase.

The enzymes that deal with toxic oxygen-containing molecules is/are

Chemoheterotrophs

In nature, bacteria

What would true about an organism called Bacillus fastidiosus?

Humans and the Microbial World

The Molecules of Life

Microscopy and Cell Structure

Control of Microbial Growth

Microbial Metabolism: Fueling Cell Growth

The Blueprint of Life, From Dna to Protein

Bacterial Genetics

Biotechnology

Identifying and Classifying Microorganisms

The Diversity of Bacteria and Archaea

The Eukaryotic Members of the Microbial World

Viruses, Viroids, and Prions

The Innate Immune Response

The Adaptive Immune Response

Host-Microbe Interactions

Immunological Disorders

Applications of Immune Responses

Epidemiology

Antimicrobial Medications

Respiratory System Infections

Skin Infections

Wound Infections

Digestive System Infections

Blood and Lymphatic Infections

Nervous System Infections

Genitourinary Tract Infections

Microbial Ecology

Environmental Microbiology: Treatment of Water, Wastes, and Polluted Habitats

Food Microbiology

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